This randomized, blinded, parallel group trial will recruit and follow 150 moderately hypercholesterolemic men and women randomly assigned to replace 160 cal of dietary protein with 40g of soy protein containing variable amounts os isoflavones to test the hypothesis that daily consumption of phytoestrogen-containing isoflavones will improve plasma concentrations of lipids and lipoproteins in a dose-dependent fashion. We will evaluate the effect of phytoestrogens on other parameters of lipid metabolism and artery function and obtain pharmacokinetics.